Spinal canal stenosis is caused by degeneration of an intervertebral disk interposed between adjacent vertebral bodies, degenerative facet joint disease, secondary deformation of a vertebral body, spinal deformation, or the like, and results in cauda equina/nerve root disorders.
One approach to treating such spinal canal stenosis includes interbody fusion in which a degenerated intervertebral disk is removed from between adjacent vertebral bodies, and then an autologous bone graft is implanted into the intervertebral space to fuse the two vertebral bodies together.
However, in a case where only bone grafting into an intervertebral space is carried out, there is a possibility that spinal instability is caused by resorption of a bone graft until bone fusion is achieved.
As a method for preventing such spinal instability, there is known a method in which an interspinous spacer is inserted into a space between adjacent spinous processes.
In the meantime, conventionally, as for surgical instruments for use in a surgical operation for inserting such an interspinous spacer into a space between adjacent spinous processes, various types of instruments have been proposed (for example, see Japanese Utility Model Registration Publication No. 2550758).
The surgical instrument disclosed in the above-mentioned prior art has a structure in which soft resin bodies are attached to inner surfaces of grasping sections, respectively, to grasp an interspinous spacer or the like directly between the soft resin bodies.
However, since such a surgical instrument grasps an interspinous spacer directly, there is a case that the interspinous spacer is damaged by an excessive grasping force or the like. Further, since the interspinous spacer is not always grasped in a predetermined portion of the instrument, it is necessary to confirm as to whether or not an interspinous spacer is inserted into a proper direction each time upon the insertion thereof, which results in a problem in that the surgical operation becomes complicated.